|Description:||In the cortex of the thymus illions of lymphocytes are produced here
each day and these are, by definition, T llymphocytes. The cortex
appears darker in low power due to the tight packing of these small
lymphocytes. Most of the lymphocytes here die by apoptosis and the dead
cells / apoptotic bodies are removed by macrophages. Some lymphocytes
migrate to the medulla and enter the circulation. In the cortex, the
lymphocytes occur in clusters surrounded by epithelial reticular cells.
This is a low power micrograph and not all of the features discussed
can be seen easily. PK2966-14. H&E. Thymus, cortex. Immune System.